1. Field of Invention
The present invention relates generally to flow rate sensing apparatus, and particularly to micro-fluidic methods applied to cylinder head gaskets for internal combustion engines. More specifically, the invention relates to apparatus and methods for measuring temperatures of fluids passing through apertures of cylinder head gaskets.
2. Description of the Prior Art
It is known to employ electronic sensors in cylinder head gaskets for sealing between engine components including, for example, the block and cylinder head of a multi-cylinder internal combustion engine. In one case, the gasket comprises a sealing plate having several combustion chamber orifices, and combustion chamber sealing elements at the edges of the sealing plate surrounding the combustion chamber orifices. The gasket includes sensor elements for cylinder-specific detection of sealing movements perpendicular to the plane of the sealing plate, caused by pressure changes in respective combustion chambers being measured. All of the sensor elements are arranged outside of the combustion chamber sealing elements and can be piezoelectric and piezoresistive, as well as glass fiber lightguide-style sensors.
In another example, a gasket enclosed sensor system is employed for measurement of combustion chamber parameters and delivery of signals to points external of the engine. The gasket includes a combustion opening substantially surrounding a combustion chamber, and includes an access opening extending from the combustion chamber to a point external of the engine. A metallic sensor terminal is positioned within the access opening, and insulating material substantially surrounds the metallic sensor terminal.
In yet another example, an oil flow sensor and associated circuitry are used to indicate presence of oil flow in a multi-cylinder internal combustion engine. The oil sensor includes a heating element positioned within the oil line, directly in the oil flow path. A comparator measures the value of signals from upstream and downstream heat sensors, and triggers a switching circuit when the temperature at the sensors approach one another to indicate an adequate oil flow to the engine. The disclosed oil flow sensor, however, is not associated with a combustion chamber gasket environment.